The long term goal of this Phase 2 SBIR program is to provide a highly effective, minimally-invasive treatment option for patients suffering from small, broad-necked intracranial aneurysms. To address the unmet clinical need for treating small broad-necked aneurysms, Sequent Medical, Inc., has developed the Woven EndoBridge, or WEB device. The WEB represents a fundamental change in the treatment of this important subset of aneurysms; in its current form, developed under a previous Phase 1 SBIR, the WEB is readily placed into broad-necked, bifurcation aneurysms and results in rapid cessation of flow into the aneurysm, without need for an intraluminal support device or antiplatelet therapy. The original WEB received regulatory approval for use in European Union countries as well as Chile, Argentina, Colombia, Australia and the United Arab Emirates and has been placed into more than 1500 aneurysms worldwide, mostly in medium-sized aneurysms; it is currently being studied under an Investigational Device Exemption (IDE) trial in the US. Current safety and efficacy data are highly promising. Notwithstanding the substantial success of the original WEB, important issues, patient groups, and markets remain to be fully addressed. Application of the WEB device to small aneurysms, both ruptured and unruptured, has been limited because of the relatively large-sized access catheters required to place the current WEB devices. The current WEB devices require catheters substantially larger than standard microcatheters of 0.017 inner diameter (017 microcatheters) used to treat aneurysms. Over the past two years, the Sequent engineering team has made rapid progress in down-sizing the profile of later-generation WEB devices. The newest WEB devices (Single Layer (SL) and Single Layer Spherical (SLS)) can be placed through customized 021 microcatheters, which are still too large to facilitate treatment of the most common sizes of ruptured aneurysms. Thus, we propose here to proceed with development of an innovative WEB device targeting treatment of small broad-necked aneurysm, including those that are ruptured. This will entail re-engineering the WEB device for use with 017 microcatheters (Aim 1) and retesting the device in a standard model system with Dr. Kallmes at the Mayo Clinic (Aim 2). Our experience with the original WEB stands as a Phase I-equivalent proof-of-concept that WEB devices are feasible and of great medical utility; indeed, our original work was so rapidly completed that we proceeded with development phases independently, rather than waiting for a Phase II SBIR. Thus, while independently pursuing an IDE on the original WEB device (our originally intended Phase II), we now propose a Direct Phase II to adapt the WEB for use in standard-sized access catheters in aneurysms of any morphology and thus markedly expand the anticipated utility of the device. At the successful conclusion of this Phase II SBIR, we will be poised to study the newly adapted WEB-017 device in an IDE. Notably, the progress of the current WEB model reduces the regulatory and technical risk for the development of this new device, which would provide a breakthrough in the treatment of small broad-necked aneurysms.